Fuse plug



Patented Oct. 6, 1925.

UNITED STATES OSCAR H. JUNG, OF MILWAUKEE WISCONSIN.

FUSE PLUG.

Application filed February 9, 1924. Serial No. 691,621.

To a whom it may concern I Be it known that I, Oscar. H. .l'rxo. citizen of the United States. and resident of Milwaukee, in the county of ltlilwaukce and State of \Visconsin, have invented certain new and useful Improvements in Fuse Plugs; and I do hereby declare that the following is a full, clear, and exact description thereof.

This invention relates to fuse plugs. As is well known it is difficult to determine. in the usual type of fuse plugs. whether or not the fuse has melted.

Attempts have been made to indicate this condition but these attempts have not wholly met the necessary conditions. F or instance. the semi-transparent cap frequently becomes so clouded that it is difficult to tell whether or not the fuse has melted and the various mechanical means heretofore employed have been either too expensive or have been uncertain or unreliable in operation.

This invention is designed to overcome the above noted defects, and objects of such invent-ion are to provide a fuse plug with effective means whereby the integrity of the fuse may be determined, to provide means whereby the testing of the fuse may be quickly made, and to provide a construction of fuse plug which is inexpensive, which is simple, and which is thoroughly reliable in operation.

An embodiment of the invention is shown in the accompanying drawing, in which 2- Figure l is a view of a fuse plug with part of the casing broken away to more clearly show the construction.

Figure 2 is a similar view of a modified form.

The fuse plug may be of any of the usual types and comprises a casing 1 on which is carried the screw threaded ferrule 2 and the central contact 3. Within the casing a fuse 4 is positioned and joins the central contact and the ferrule in the usual manner,it being customary to provide the looped portion 5 of the fuse of a smaller cross sec tional arrangement than theremaining portions. The casing 1 is completed in any suitable manner as by means of a metal cap 6 clamped around the edge of the casing as shown. This metal cap is provided with an a rture 7 in the form shown in Figure 1. 'Flie indicating means or the testing means for determining the continuity of the fuse may comprise a looped non-combustible member 8 which interlinks with the fuse and has its ends projecting through the aperture 7 in the cap (5. The ends are bound together or pernnmently joined by means of a member 9 which may be formed in any suitable manner. This n'iember may be a knot tied in the strings 8. for instance. or may be an enlargement such as sealing wax. or a metal cap. It indicated generally at 9 in Figure 1.

The operation of the apparatus is as follows z-lVhen it is desired to test whether or not. he fuse has melted. it merely ne es sary to grasp the member 9 and pull upon the looped strands S. If the fuse has melted the member S may be readily withdrznvn. whereas on the other hand if the fuse is still continuous. the withdrawal of the member 8 is prevented. H is well known that these fuse plugs are usually installed in a relatively poorly lighted place, and in an out of the way place. thus it is difficult to determine whether or not the fuse is still efl'ec tive. However. with this invention, the on erator may quickly test the several fuse plugs and may easily locate the melted fuse.

The member 8 may be of any suitable inn-- terial which is preferably non-comlmstible A convenient material for this use is ashes tos. although. obviously. other materials could be employed. It is also to be noted that the member 8 does not form a hermetical seal for the aperture 7 but that there is in effect a vent for the expanding gases due to the melting of the fuse ind the heat incident thereto.

In the form shown in Figure 2. the same general construction of fuse plug is employed as that previously described. The metal cap 6. however. is imperforate in this form of the invention. and an aperture 10 is formed adjacent the outer end of the cylindrical casing 1. Through this a ierture the looped member 8' is passed and is preferably provided with binding portion 9 joining the terminals of the strand.

It is to be noted that the direction of pull of the member 8' is slanting with reference to the axis of the fuse plug and is directly away from the general line of the two loop of the fuse. I

It will be seen from the description and drawings that an extremely simple very cheap form of testing means or indicating end secured to said ferrule and having a combustible flexible member passing through said loop and extending outwardly from 881d bodyportion and adapted to be drawn rear- 2H wardly to test the continuity of said fusible element, whereby when said member is drawn upon the stress is transmitted longitudinally to both strands ofsaid fusible element.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee,-in the county of Milwaukee and State of Visconsin.

iearwardly extendingdooped portion, a non- OSCAR H. JUNG. 

